1. Field of the Invention
The present invention relates to a measurement apparatus and its method for a flying height of a disk drive head.
2. Description of the Related Art
Various methods, such as optical interference, have conventionally been adopted for measuring a flying height of a reading head from a recording surface (i.e., a magnetic layer) for a disk drive.
In the case of measuring a flying height of a head on a track by using a simple output amplitude such as a conventional technique called TAA (Track Averaged Amplitude; i.e., an average amplitude of one round of a track), et cetera, measurement errors may be induced by output changes due to an off-track displacement of the head and/or a secular change of an output sensitivity.
In order to solve the above described problem, proposed is a method called a Triple Harmonic Method for measuring a flying height of ahead. The triple harmonic method is one for recording a specific magnetization pattern (e.g., “1, 1, 1, 1, 0, 0”) so as to include many linear harmonic components and cubic harmonic components of waves in a hard disk in advance, and measure a head flying height by reading an amplitude ratio of components of the magnetization pattern.
The above described triple harmonic method, however, requires a process for writing a specific-use magnetization pattern in advance to a hard disk as the target of measuring a head flying height, and therefore faced with the problem of increased processes. Another problem is that an effective recording zone of a hard disk product reduces because the above described specific-use magnetization pattern occupies a part of the recording zone of the hard disk.
Considering the above described problem, the present invention aims at providing an apparatus, and the related method and program which are capable of providing a new measurement of a head flying height which does not require a specific-use magnetization pattern.